1. Field of the Invention
This invention is related in general to erasing devices and, in particular, to applicators for removing highlighting inks and colorings from a substrate surface containing written or printed material.
2. Description of the Prior Art
Many brand names and varieties of markers exist for the purpose of emphasizing printed or written material and of highlighting particular areas of a paper surface. For example, one such commercial type of marker is produced by Carter's Ink Company of Cambridge, Mass., and is known by the trademark "HILITER.RTM.."
Typically, these emphasizing markers use pastel or fluorescent shades of transparent or translucent inks or dyes which are water-based and non-pigmented. Such highlighting inks and dyes are generally applied by rubbing a liquid-saturated, felt-tipped applicator across or around the paper surface that is to be highlighted and generally over a permanent, pigmented type of ink marking that is being emphasized. The paper surfaces typically are photocopies, books, drawings, newsprint, documents or other similar papers having rather permanent, pigmented type of ink or print thereon.
Highlighting is so easy to apply that it is often overused; mistakes are easy to make and most unfortunately many of the highlighted-surface colors are reproduced as gray-shaded areas on photocopies. It is therefore highly desirable to provide a means for erasing, eradicating or otherwise removing these highlighting inks or dyes from paper or other substrate surfaces with little or no effect on the underlying printed, written or photocopied text and without material damage to the paper or other surface.
A few products have been introduced in the market to fulfill this need. For example, U.S. Pat. No. 3,941,488 to Maxwell (1976) describes a marker/eraser combination designed to provide the ability to erase the markings produced by the marker by utilizing specific chemical reagents. The idea of the patent is to combine each marker ink with a corresponding erasing reagent capable of removing the ink without affecting the underlying text and substrate. One of the patent's stated objectives is to avoid using bleaches, which not only bleach many inks but also any color present in the writing paper.
A comparable approach is followed by Hayduchok et al. in U.S. Pat. No. 4,681,471 (1987), where a kit is disclosed comprising a combination of markers and an erasing unit where the chemical constituents of the dyes are chosen to be compatible for eradication by a specific reducing agent. The patent describes these chemicals in detail and is limited to combinations thereof.
Similarly, the Carter's Ink Company has also marketed an ink eraser (RYTOFF.RTM.) based on bleaching ingredients to remove pen writings. Because of the method of application of the bleaching agent, blotting of excess reagent is necessary to avoid damage to the substrate. Experiments have shown that this product does not generally remove inks other than water-based non-pigmented inks (the instructions specifically exclude ball-pen inks). In addition, this product is intended for use with writings produced by pens, but not to erase markings produced by their HILITER.RTM. or other markers.
Therefore, there still exists a need for a generic eraser suitable for use with a wide class of markers, rather than coupled to markers having specific reagent characteristics. In particular, inasmuch as most markers available today are based on water-based, non-pigmented dyes, it would be very desirable to have a product capable of erasing markings produced by any of them.